# How to Make An Electric Piano Circuit?

In this article we will look at how to make an Electric Piano circuit using 555 timer integration and several other electronic components. This circuit consists of a series of push button switches (similar to different keys on the piano) that produce sounds of different shades through a speaker when pressed.

The frequency of the output tones can also be adjusted more precisely by calculating the exact values of the resistors to be used. The frequency calculation formula is located at the bottom of this content.

## Required Materials

• 555 Timer Integrated
• 8 Ohm Speaker
• 6 x Instant Button Switch
• Capacitors: 100nF, 10uF
• Resistors: 6 x 1K, 4.7K
• Jumper/Cables
• (5-9) V Power Supply

## Working principle

In one of the previous tutorials(using the 555 Integrated in astable mode and burning LED), welearned how changing the resistance value serially with the capacitor changes the blink rate (Frequency).And this relationship is inversely proportional, that is, if the value of resistance to the capacitor in series is large, the frequency will be less, and vice versa.You can refer to this content to better understand how resistance and capacitor values affect the output frequency.

Formula for calculating the frequency of the output sound/tone:

Frequency (f) = 1.44 / ( (R1 + 2 * R2) x C1 )

In our circuit, the value of R1 is 1K and the value of C1 is 100n.After changing these values in the formula above, we have:

Frequency (f) = 1.44 / ( (1000 + 2 * R2) x 10-7)

In addition, we can rearrange the formula to calculate the value of resistance that we must use for any required frequency:

Resistance (R2) = ( ( 1.44 x 107) / f ) – 500